As usual he just ’emerged’, came up, with no fanfare.
The way to tell he wasn’t there long is the divot of water in the duck weed where he surfaced. No noise, bubbles, or any real motion.
Alligators can change their center of gravity. This controls if, or how, they float. One position (internal) and they gentle sink straight down, another and they rise up.
Here the Alligator was about 2 meters from the waters edge. Nothing can sneak up on them here. Even a four foot Alligator must be a little careful.